| Recent
Advances in Medical Applications of Synchrotron Radiation Stanford Synchrotron Radiation Laboratory March 4-5, 2002 Program Director: Edward Rubenstein |
 < a href="Rubenstein-Workshop.pdf">PDF of all abstracts |
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Quantitative
Functional Lung Imaging with Synchrotron Radiation using Inhaled
Xenon as Contrast Agent
< br> W. Thomlinson1, S. Bayat1,2, G. Le Duc1, S. Monfraix1, G. Berruyer1, T. Brochard1, C. Nemoz1, L. Porra3, P. Suortti3, C.G. Standertskjöld-Nordenstam4 and A.R.A. Sovijärvi5 1European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France 2TIMC-PRETA, UMR CNRS 5525, Laboratoire de Physiologie, Université Joseph Fourier, Faculté de Médicine, Domaine de la Merci, F-38700 La Tronche, France 3Department of Physics, POB 64, FIN-00014 University of Helsinki, Finland 4Department of Radiology, University of Helsinki Central Hospital, POB 340, FIN-00029 HUS, Finland 5Department of Clinical Physiology and Nuclear Medicine, Helsinki University Central Hospital, POB 340, FIN-00029 HUS, Finland |
| Small
airways play a key role in the distribution of ventilation, and in
the matching of ventilation to perfusion. The purpose of this study
is to introduce an imaging method that allows the measurement of regional
lung ventilation and to evaluate the function of airways with a small
diameter. The experiments are performed at the Medical Beamline of the European Synchrotron Radiation Facility. Monochromatic synchrotron radiation beams are used to obtain quantitative, respiration-gated, K-Edge subtraction images of lungs and airways in anae sthetized and mechanically ventilated rabbits using inhaled stable xenon (Xe) gas as contrast agent. Two-dimensional projection and tomographic images are obtained showing spatial distribution of Xe concentrations within the airspaces, as well as the dynamics of filling with Xe. Bronchi down to 1 mm in diameter are visible both in the subtraction radiographs and in tomographic images. Absolute concentra tions of Xe gas are calculated within the tube carrying the inhaled gas mixture, small and large bronchi, and lung tissue. Local time constants of ventilation with Xe can be obtained by following the evolution of gas concentration in sequential computed tomography images. The results of these initial studies indicate that KES imaging of lungs with Xe gas as contrast agent has a great potential in studie s of the distribution of ventilation within the lungs and of airway function. |
